Online Etymology Dictionary

recursion (n.): 1610s, from Latin recursionem (nominative recursio) "a running backward, return," noun of action from past participle stem of recurrere "run back" (see recur).
recursive (adj.): 1790, "periodically recurring," from Latin recurs-, stem of recurrere (see recur) + -ive. Mathematical sense is from 1934. Related: Recursively; recursiveness.
recusal (n.): 1911; from recuse + -al (2). Earlier were recusancy (1560s), recusance (1590s).
recusant (adj.): "obstinate in refusal," 1550s, from Latin recusantem (nominative recusans) "refusing to obey," present participle of recusare "make an objection against; decline, refuse, reject; be reluctant to" (see recuse). The noun meaning "one obstinate in refusing" is from 1610s.
recuse (v.): late 14c., "to reject another's authority as prejudiced," from Old French recuser (13c.), from Latin recusare "make an objection against; decline, refuse, reject; be reluctant to," from re- (see re-) + causa (see cause (n.)). Specifically, in law, "reject or challenge (a judge or juror) as disqualified to act." The word now is used mostly reflectively. Related: Recused; recusing.
recyclable (adj.): 1971, from recycle + -able. As a noun, by 1973. Related: Recyclables.
recycle (v.): 1922, originally of industrial processes; see re- + cycle (v.). Specifically of waste material from 1960. Related: Recycled; recycling.
recycling (n.): 1924, verbal noun from recycle (v.). Originally a technical term in oil-refining and similar industries; its broader consumer sense dates from 1960.
red (adj.1): Old English read "red," from Proto-Germanic *raudaz (source also of Old Norse rauðr, Danish rød, Old Saxon rod, Old Frisian rad, Middle Dutch root, Dutch rood, German rot, Gothic rauþs). As a noun from mid-13c.

The Germanic words are from PIE root *reudh- "red, ruddy" (source also of Latin ruber, also dialectal rufus "light red," mostly of hair; Greek erythros; Sanskrit rudhira-; Avestan raoidita-; Old Church Slavonic rudru, Polish rumiany, Russian rumjanyj "flushed, red," of complexions, etc.; Lithuanian raudas; Old Irish ruad, Welsh rhudd, Breton ruz "red"). The only color for which a definite common PIE root word has been found. The initial -e- in the Greek word is because Greek tends to avoid beginning words with -r-.

Along with dead, bread (n.), lead (n.1), the vowel shortened in Middle English. The surname Read/Reid retains the original Old English long vowel pronunciation and is the corresponding surname to Brown-, Black, White.

The color designation of Native Americans in English from 1580s. The color as characteristic of "British possessions" on a map is attested from 1885. Red-white-and-blue in reference to American patriotism, from the colors of the flag, is from 1840; in a British context, in reference to the Union flag, 1852. The red flag was used as a symbol of defiance in battle on land or sea from c. 1600. To see red "get angry" is an American English expression first recorded 1898. Red rover, the children's game, attested from 1891. Red light as a sign to stop is from 1849, long before traffic signals. As the sign of a brothel, it is attested from 1899. As a children's game (in reference to the traffic light meaning) it is recorded from 1953.

Red-letter day (late 14c.) was originally a saint's day, marked on church calendars in red letters. Red ball signifying "express" in railroad jargon is 1904, originally (1899) a system of moving and tracking freight cars. Red dog, type of U.S. football pass rush, is recorded from 1959. Red meat is from 1808. Red shift in spectography is first recorded 1923. Red carpet "sumptuous welcome" is from 1934, but the custom for dignitaries is described as far back as Aeschylus ("Agamemnon"); it also was the name of a type of English moth.
red (adj.2): "Bolshevik," 1917, from red (adj.1), the color they adopted for themselves. Association in Europe of red with revolutionary politics (on notion of blood and violence) is from at least 1297, but got a boost 1793 with adoption of the red Phrygian cap (French bonnet rouge) as symbol of the French Revolution. First specific political reference in English was 1848 (adj.), in news reports of the Second French Republic (a.k.a. Red Republic). Red China is from 1934. The noun meaning "radical, communist" is from 1851.
red cent (n.): obsolete type of copper penny, 1839, American English, from red (adj.1) + cent. "Red" has been the color of copper, brass, and gold since ancient times.
red cross (n.): early 15c., national emblem of England (St. George's Cross), also the badge of the Order of the Temple. Hence red-cross knight, one bearing such a marking on shield or crest. In 17c., a red cross was the mark placed on the doors of London houses inflected with the plague. Red Cross (in Muslim lands, red crescent) adopted as a symbol of ambulance service 1864 by the Geneva Conference.
red herring (n.): "smoked herring" early 15c. (they turn red when cured), as opposed to white herring "fresh herring." Supposedly used by fugitives to put bloodhounds off their scent (1680s), hence metaphoric sense (1864) of "something used to divert attention from the basic issue;" earlier simply "a false lead":
Though I have not the honour of being one of those sagacious country gentlemen, who have so long vociferated for the American war, who have so long run on the red-herring scent of American taxation before they found out there was no game on foot; (etc.) [Parliamentary speech dated March 20, 1782, reprinted in "Beauties of the British Senate," London, 1786]
red ink (n.): "financial losses," 1929, from the red ink traditionally used to indicate debits in accounts.
Red Sea (n.): the Greek thalassa erythra; the reason for the name is unknown; speculation has traced it to: 1. algae in coastal waters; 2. sandstone rock formations on the shores; 3. a tribal name; 4. ancient association of "red" with "south" (as "black" with "north").
red tape (n.): "excessive bureaucratic rigmarole," 1736, in reference to the red tape formerly used in Great Britain (and the American colonies) for binding up legal and other official documents, mentioned from 1690s.
red-blooded (adj.): "having red blood," 1802, from red (adj.1) + blood (n.). Figurative meaning "vigorous, spirited" is recorded from 1877.
red-eye (n.): "airplane flight which deprives travelers of sleep," 1968, from the red eyes of sleeplessness; earlier as a noun meaning "raw and inferior whiskey" (1819, American English).
red-handed (adj.): 1781, earlier red-hand (early 15c.), originally in Scottish legal writing, from red (adj.1) + -handed; presumably from the image of a murderer with hands still stained with blood.
red-hot (adj.): late 14c., "heated till it glows red" (of metal, etc.); of persons, "lively, passionate," it is recorded from c. 1600. Red-hot mama is 1926, jazz slang, "earthy female singer," also "girlfriend, lover."
red-streak (n.): type of apple prized for cider-making, 1660s, from red (adj.1) + streak (n.).
redact (v.): early 15c., "bring into organized form," from Latin redactus, past participle of redigere "to drive back, force back; bring back; collect, call in; bring down, reduce," from re- "back, again" (see re-) + agere "to drive" (see act (n.)). Specific meaning "arrange, edit" is from 1851.
redaction (n.): "editing for publication," 1785, from French rédaction "a compiling; a working over, editing; editorial staff" (late 17c.), from Late Latin redact-, past participle stem of redigere (see redact). Meaning "a redacted version" is from 1810. Earlier it meant "a driving back" (1620s).
redbird (n.): mid-13c., a name for sundry red or partly red birds, including the common bullfinch and the scarlet tanager, but in U.S. especially the cardinal, from red (adj.1) + bird (n.).
redbreast (n.): early 15c., of the English robin, from red (adj.1) + breast (n.). Later of the American bird.
redcap (n.): "porter at a railroad station," 1914, American English, from red (adj.1) + cap (n.). Earlier it was the name of the goldfinch, a type of hen, and a long-toothed spectre in Scottish castles.
redcoat (n.): "British soldier," 1510s, from red (adj.1) + coat (n.). In Britain, especially of Cromwellian troops in the English Civil War; in the U.S., of British soldiers in the American Revolution.
redd (v.): early 15c., "to clear" (a space, etc.), from Old English hreddan "to save, free from, deliver, recover, rescue," from Proto-Germanic *hradjan. Sense evolution tended to merge with unrelated rid. Also possibly influenced by Old English rædan "to arrange," related to Old English geræde, source of ready (adj.).

A dialect word in Scotland and northern England, where it has had senses of "to fix" (boundaries), "to comb" (hair), "to separate" (combatants), "to settle" (a quarrel). The exception to the limited use is the meaning "to put in order, to make neat or trim" (1718), especially in redd up, which is in general use in England and the U.S. Use of the same phrase, in the same sense, in Pennsylvania Dutch may be from cognate Low German and Dutch redden, obviously connected historically to the English word, "but the origin and relationship of the forms is not clear" [OED].
redden (v.): "become red; make red," late 14c., from red (adj.1) + -en (1). Old English had readian, reodian "become red." Related: Reddened; reddening.
redder (n.): "one who sets or puts in order," especially "one who tries to settle a quarrel," mid-15c., Scottish, agent noun from redd (v.).
reddish (adj.): late 14c., from red (adj.1) + -ish. Related: Reddishness.
rede (n.): "counsel, advice," Old English ræd "advice, counsel;" see read (v.). Cognate with Old Saxon rad "advice, counsel, help, advantage," Dutch raad "advice, counsel," German Rat "advice, counsel," Old Norse rað "advice, consideration, remedy, power; marriage."
redeem (v.): early 15c., "buy back, ransom," from Middle French redemer "buy back," from Latin redimere (see redemption). Theological sense of "deliver from sin and spiritual death" is from c. 1500. Meaning "make amends for" is from 1520s. Sense of "make good" (a promise, obligation, etc.) is from 1840. Related: Redeemed; redeeming.
redeemable (adj.): 1610s, from redeem + -able.
redeemer (n.): early 15c., agent noun from redeem. Originally in the Christian sense, "Savior of the world, Jesus Christ;" it replaced earlier redemptor.
redefine (v.): 1848, from re- + define. Related: Redefined; redefining; redefinition.
redemption (n.): mid-14c., "deliverance from sin," from Old French redemcion (12c.) and directly from Latin redemptionem (nominative redemptio) "a buying back, releasing, ransoming" (also "bribery"), noun of action from past participle stem of redimere "to redeem, buy back," from red- "back" (see re-) + emere "to take, buy, gain, procure" (see exempt). The -d- is from the Old Latin habit of using red- as the form of re- before vowels. In the Mercian hymns, Latin redemptionem is glossed by Old English alesnisse.
redemptioner (n.): "indentured servant," 1775, from redemption + -er (1).
REDEMPTIONER. One who redeems himself or purchases his release from debt or obligation to the master of a ship by his services; or one whose services are sold to pay the expenses of his passage to America. [Webster, 1830]
redemptive (adj.): 1640s, from redempt (mid-15c.), adjective from Latin redemptus, past participle of redimere (see redemption) + -ive. Related: Redemptively.
Redemptorist (n.): member of the Congregation of the Most Holy Redeemer (founded Naples, 1732, by St. Alphonsus Liguori), 1835 in English. Fem. form is Redemptoristine.
redeploy (v.): 1945, in reference to U.S. troops shifting from Europe to Asia after the fall of Berlin, from re- + deploy. Related: Redeployed; redeploying.
redeployment (n.): 1945, from re- + deployment.
redesign (v.): 1843, from re- + design (n.). Related: Redesigned; redesigning.
redesign (n.): 1881, probably from redesign (v.).
redevelopment (n.): also re-development, 1830, from re- + development.
redfish (n.): 15c., of various species, especially originally the male salmon in spawning season; from red (adj.1) + fish (n.).
redhead (n.): mid-13c., from red (adj.1) + head (n.). Red (adj.), of persons, "having red hair" is from late Old English.
The Carrot pate be sure you hate, for she'l be true to no man,
But put her too 't and she will do 't, and oft turns very common:
She that is red upon the head will doubtless ne'r forsake it,
But wanton be, assuredly, and willingly will take it.
["The True Lover's Admonition," Roxburghe Ballads, c. 1680]
redial (v.): also re-dial, 1961, from re- + dial (v.). Related: Redialed; redialing.
redingote (n.): "double-breasted outer coat with long plain skirts," also a similar garment for women, 1793, from French redingote (1725) from English riding coat (c. 1500).
redirect (v.): 1805 (implied in redirected), from re- "back, again" + direct (v.). Related: Redirecting.